Commit-ID: 2dee9404fa8c4384453a5f3a15ad74ab9480f2d6
Gitweb: http://git.kernel.org/tip/2dee9404fa8c4384453a5f3a15ad74ab9480f2d6
Author: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
AuthorDate: Tue, 11 Jul 2017 21:52:31 -0700
Committer: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
CommitDate: Thu, 17 Aug 2017 07:26:23 -0700
rcu: Add assertions verifying blocked-tasks list
This commit adds assertions verifying the consistency of the rcu_node
structure's ->blkd_tasks list and its ->gp_tasks, ->exp_tasks, and
->boost_tasks pointers. In particular, the ->blkd_tasks lists must be
empty except for leaf rcu_node structures.
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
---
kernel/rcu/tree.c | 2 ++
kernel/rcu/tree_plugin.h | 11 +++++++++--
2 files changed, 11 insertions(+), 2 deletions(-)
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 2b37f1a..ac2617d 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -2410,6 +2410,8 @@ rcu_report_qs_rnp(unsigned long mask, struct rcu_state *rsp,
return;
}
WARN_ON_ONCE(oldmask); /* Any child must be all zeroed! */
+ WARN_ON_ONCE(rnp->level != rcu_num_lvls - 1 &&
+ rcu_preempt_blocked_readers_cgp(rnp));
rnp->qsmask &= ~mask;
trace_rcu_quiescent_state_report(rsp->name, rnp->gpnum,
mask, rnp->qsmask, rnp->level,
diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index 3e3f92e..eadf8b9 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -180,6 +180,8 @@ static void rcu_preempt_ctxt_queue(struct rcu_node *rnp, struct rcu_data *rdp)
struct task_struct *t = current;
lockdep_assert_held(&rnp->lock);
+ WARN_ON_ONCE(rdp->mynode != rnp);
+ WARN_ON_ONCE(rnp->level != rcu_num_lvls - 1);
/*
* Decide where to queue the newly blocked task. In theory,
@@ -261,6 +263,10 @@ static void rcu_preempt_ctxt_queue(struct rcu_node *rnp, struct rcu_data *rdp)
rnp->gp_tasks = &t->rcu_node_entry;
if (!rnp->exp_tasks && (blkd_state & RCU_EXP_BLKD))
rnp->exp_tasks = &t->rcu_node_entry;
+ WARN_ON_ONCE(!(blkd_state & RCU_GP_BLKD) !=
+ !(rnp->qsmask & rdp->grpmask));
+ WARN_ON_ONCE(!(blkd_state & RCU_EXP_BLKD) !=
+ !(rnp->expmask & rdp->grpmask));
raw_spin_unlock_rcu_node(rnp); /* interrupts remain disabled. */
/*
@@ -482,6 +488,7 @@ void rcu_read_unlock_special(struct task_struct *t)
rnp = t->rcu_blocked_node;
raw_spin_lock_rcu_node(rnp); /* irqs already disabled. */
WARN_ON_ONCE(rnp != t->rcu_blocked_node);
+ WARN_ON_ONCE(rnp->level != rcu_num_lvls - 1);
empty_norm = !rcu_preempt_blocked_readers_cgp(rnp);
empty_exp = sync_rcu_preempt_exp_done(rnp);
smp_mb(); /* ensure expedited fastpath sees end of RCU c-s. */
@@ -495,10 +502,10 @@ void rcu_read_unlock_special(struct task_struct *t)
if (&t->rcu_node_entry == rnp->exp_tasks)
rnp->exp_tasks = np;
if (IS_ENABLED(CONFIG_RCU_BOOST)) {
- if (&t->rcu_node_entry == rnp->boost_tasks)
- rnp->boost_tasks = np;
/* Snapshot ->boost_mtx ownership w/rnp->lock held. */
drop_boost_mutex = rt_mutex_owner(&rnp->boost_mtx) == t;
+ if (&t->rcu_node_entry == rnp->boost_tasks)
+ rnp->boost_tasks = np;
}
/*
--
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